The invention relates to a viewing apparatus having a viewing optic for viewing an object. The object is viewed along a viewing beam path and the viewing apparatus further includes an illuminating device for illuminating the object along an illuminating beam path running in segments transverse to the viewing beam path.
A viewing apparatus of the above kind and configured as a stereoscopic surgical microscope is disclosed, for example, in U.S. Pat. No. 5,126,877. The viewing optic of this surgical microscope includes a main objective through which both stereo component beam paths of the viewing beam path pass and a separate zoom system is provided for each of the two stereo component beam paths. The illuminating arrangement includes two lens elements centered with respect to each other and whose optical axis runs transversely to the viewing beam path. The illuminating beam path of this stereo microscope passes through the two lens elements and, after the deflection by a deflecting element, through the primary objective whereby very favorable illuminating angles can be achieved.
U.S. Pat. No. 5,838,491 discloses a further viewing apparatus which is a stereomicroscope having an objective of variable focal intercept. Differently distanced objects or object regions can be focused with the objective having a variable focal intercept or variable work distance. In this stereomicroscope, the illuminating beam path runs outside of the objective of variable focal intercept in order to avoid reflections of the illuminating light on the viewing optic in the viewing beam path. The illuminating arrangement includes pivotable deflecting elements whose particular inclination is dependent upon the corresponding focal intercept of the objective in order to achieve the most optimal illumination for each focal intercept. This known viewing apparatus is therefore very complex as to its construction.
It is an object of the invention to provide a viewing apparatus having an improved illuminating arrangement.
The viewing arrangement of the invention includes: a viewing optical assembly for viewing an object along a viewing beam path; an illuminating assembly for illuminating the object along an illuminating beam path having a segment running transversely to the viewing beam path; and, a beam-shaping illuminating element arranged in the segment of the illuminating beam path and being configured to be asymmetrical relative to the illuminating beam path.
With the invention, the illuminating radiation can be formed in correspondence to its passage through the peripheral region of an optical element of the viewing optic. This is basically advantageous for the optimal adaptation of the illuminating beam path to the viewing beam path. In this way, problems from illuminating light reflections in the viewing beam path are significantly reduced which reflections would otherwise reduce the viewing contrast.